U.S. Pat. No. 4,919,545 issued Apr. 24, 1990 to Yu for DISTRIBUTED SECURITY PROCEDURE FOR INTELLIGENT NETWORKS, discloses a security technique for use in an intelligent network and includes steps of granting permission to an invocation node to access an object by transmitting a capability and a signature from an execution node to the invocation node thereby providing a method for authorizing a node to gain access to a network resource by using a form of signature encryption at the node.
U.S. Pat. No. 5,301,283 issued Apr. 5, 1994 to Thacker et al. for DYNAMIC ARBITRATION FOR SYSTEM BUS CONTROL IN MULTIPROCESSOR DATA PROCESSING SYSTEM discloses a data processing system having a plurality of commander nodes and at least one resource node interconnected by a system bus, and a bus arbitration technique for determining which commander node is to gain control of the system bus to access the resource node thereby providing a node lockout which prevents nodes from gaining access to the system bus.
U.S. Pat. No. 5,386,551 issued Jan. 31, 1995 to Chikira et al. for DEFERRED RESOURCES RECOVERY discloses a resources management system for fencing all autonomous resources, and a protocol is followed to allow all activities in a work stream to be completed before all fencing is removed.
U.S. Pat. No. 5,416,921 issued May 16, 1995 to Frey et al. for APPARATUS AND ACCOMPANYING METHOD FOR USE IN A SYSPLEX ENVIRONMENT FOR PERFORMING ESCALATED ISOLATION OF A SYSPLEX COMPONENT IN THE EVENT OF A FAILURE discloses an apparatus for use in a multi-system shared data environment which fences through a pre-defined hierarchical order, failed components from accessing shared data in order to protect data integrity.
U.S. Pat. No. 5,423,044 issued Jun. 6, 1995 to Sutton et al. for SHARED, DISTRIBUTED LOCK MANAGER FOR LOOSELY COUPLED PROCESSING SYSTEMS discloses apparatus for managing shared, distributed locks in a multiprocessing complex for synchronizing data access to identifiable subunits of direct access storage devices.
The Virtual Shared Disk (VSD) product, which is a component of the Parallel System Support Programs for AIX (PSSP) from the International Business Machines Corp. of Armonk, N.Y., provides raw disk access to all nodes on a RS/6000 Scalable POWERparallel (SP) system. The disk itself, however, is physically connected to only two nodes. One of these nodes is a VSD primary server, and the other is a backup server. If a disk is not locally attached, the VSD kernel extension will use Internet Protocol to route the requests to the server node. If the primary node is unavailable for any reason, access is switched to the secondary node, and the data on the disk drive may still be accessed by the secondary node.
The Group Services product of PSSP keeps a record of member nodes in a group of nodes. It is desirable to provide a fencing function to the VSD subsystem to provide fencing support.
In the case that a process instance using VSDs on node X is unresponsive, a distributed subsystem may wish to ensure that X's access to a set of virtual disks (VSDs) is severed, and all outstanding I/O initiated by X to these disks are flushed before recovery can proceed. Fencing X from a set of VSDs denotes that X will not be able to access these VSDs (until it is unfenced). Fence attributes must survive node Initial Program Loads (IPLs).